The scattered reviews from across the nation can play like a merciless irony: Somebody exams constructive for the coronavirus despite the fact that they’ve already obtained one or each doses of a Covid-19 vaccine.
It’s occurred to a minimum of three members of Congress just lately:
How can that occur?
Specialists say circumstances like these usually are not shocking and don’t point out that there was one thing incorrect with the vaccines or how they have been administered. Right here is why.
Vaccines don’t work immediately. It takes just a few weeks for the physique to construct up immunity after receiving a dose. And the vaccines now in use within the U.S., from Pfizer-BioNTech and Moderna, each require a second shot just a few weeks after the primary to achieve full effectiveness.
Nor do they work retroactively. You possibly can already be contaminated and never understand it whenever you get the vaccine — even should you just lately examined unfavorable. That an infection can proceed to develop after you get the shot however earlier than its safety totally takes maintain, after which present up in a constructive take a look at consequence.
The vaccines stop sickness, however perhaps not an infection. Covid vaccines are being approved primarily based on how properly they maintain you from getting sick, needing hospitalization and dying. Scientists don’t know but how efficient the vaccines are at stopping the coronavirus from infecting you to start with, or at holding you from passing it on to others. (That’s why vaccinated individuals ought to maintain carrying masks and sustaining social distance.)
Even the perfect vaccines aren’t excellent. The efficacy charges for Pfizer-BioNTech and Moderna vaccines are extraordinarily excessive, however they aren’t 100 %. With the virus nonetheless spreading uncontrolled within the U.S., a few of the tens of millions of just lately vaccinated individuals have been certain to get contaminated in any case.